The popularity and convenience of the Internet has resulted in the reinvention of traditional telephony services. These services are offered over a packet switched network with minimal or no cost to the users. IP (Internet Protocol) telephony, thus, have found significant success, particularly in the long distance market. In general, IP telephony, which is also referred to as Voice-over-IP (VoIP), is the conversion of voice information into data packets that are transmitted over an IP network. Users also have turned to IP telephony as a matter of convenience in that both voice and data services are accessible through a single piece of equipment, namely a personal computer. Furthermore, traditional DTMF (Dual-Tone Multi-Frequency) phones can enjoy the benefits of VoIP technology through the use of network adapters. The continual integration of voice and data services further fuels this demand for IP telephony applications.
Conventional IP telephony systems face a number of engineering challenges, which have hindered the deployment of IP telephony services to residential and small business consumers (i.e., Small Business or Home Office). One reason for this hindrance is the difficulty in routing incoming SIP (Session Initiation Protocol) telephone calls that originate in the public switched telephone network (PSTN); SIP has emerged as the underlying signaling protocol for IP telephony systems. The emergence of electronic numbers (ENUM) does help address this problem; however, ENUM lacks wide spread deployment by current service providers.
Another reason is that some important traditional telephony services cannot be implemented with existing IP telephony systems. These services include routing of outgoing local calls with LNP (Local Number Portability), E911, Local Operator, directory assistance (DA), and operator Break in and busy line verification (BLV). Because calls in the PSTN are routed based on the dialed number, it is necessary to deploy one gateway per LATA (Local Access and Transport Area) in which the service is offered. Gateways with special local trunks such as 911, Operator, DA, etc. and access to a LNP database are required. The deployment of these gateways in every LATA is costly, and represents a significant hurdle for the SOHO market.
Therefore, there is a need for an approach for efficiently performing telephony services over an IP telephony communications system. There is also a need to preserve a standard architecture to promote deployment of network services, while minimizing system complexity.